Solana is preparing its Alpenglow upgrade for public testnet deployment, where developers will try to reduce transaction finality time from about 12.8 seconds to 150 milliseconds.
The rollout expands testing beyond a dedicated community network, where Alpenglow has operated for more than four months. However, Anza’s tracker still showed the testnet switch as pending on September 23, CoinDesk reported.
How Alpenglow Could Speed Up Solana Finality
Alpenglow is now being introduced on Solana’s public test network. The public testnet is a separate network where developers can test upgrades without risking funds on the mainnet. This lets developers test the migration, find issues, and restart the network without risking users’ money.
Finality marks the point when a transaction becomes part of the blockchain’s permanent record. Exchanges, bridges, and merchants all require confirmed transaction finality before releasing funds or completing payments.
Faster finality could shorten settlement waits for exchanges, cross-chain bridges, and merchants. Solana’s documentation identifies near-instant checkout confirmation as one potential benefit.
Solana currently uses the TowerBFT system to record validator votes as transactions and accumulates them across 32 slots before finalizing a block. Alpenglow replaces that system with a voting protocol called Votor. It lets validators exchange votes directly and reach finality in one or two voting rounds.
Alpenglow has spent over four months running on a smaller network created specifically for the upgrade. The migration will test whether validators and supporting services can upgrade together.
According to Solana’s documentation, Votor can finalize a block in one round with votes representing at least 80% of stake, or in two rounds using a 60% stake threshold.
The original 150-millisecond median estimate came from simulations that excluded computation overhead. The estimate is not a guaranteed finality time for every transaction.
What Alpenglow Changes for Users and Validators
Signing and sending transactions would remain unchanged for users. Alpenglow preserves Solana’s transaction execution system and fee mechanics, although infrastructure providers must adapt how they process block data.
The 150-millisecond finality target is separate from efforts to shorten block-production slots.
Participating testnet validators need Agave 4.3. Jump Crypto’s two alternative validator clients, Firedancer and Frankendancer, do not yet support the Alpenglow test.
These alternatives aim to reduce Solana’s reliance on a single piece of software. Independent validator clients can reduce the risk of a single software flaw disrupting the network.
Anza’s tentative schedule lists September 28 for resuming Agave 4.3 feature activation on mainnet.
However, it is not a confirmed Alpenglow launch date, and Anza’s tracker still showed the testnet switch as pending as of early Wednesday.
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